Cold-reducing tubular sections



April 17, 1951 J. W. OFFUTT COLD REDUCING TUBULAR SECTIONS Filed Nov. 5, 1946 r HMFi |||||||||||ll|||ll IFI INVENTORI JOH/V W4 flFFZ/TZ HIS ATTORNEY.

, Patented Apr. 17, 1951 CDIID' R'EDUCING TUBULARSECTIQNSI John W; lfutt=Ellwood City, Pa., assignor to'Naltiona'l" Tube; Company, a corporation; of: New.

Jersey;

Ap l cation November 5, 1946, Sam NQ. 707,933:

(crease-4;):

' 3-;Gelaims;

This invention relates-to improvements in the artzof cold-reducing tubular sections.

Gold-reducing tubularsections to obtain improved. physical properties, accuratedimensions and smooth surfaces whereby thinner sections may beused andimachining operations eliminated or reduced, is conventional practice. Such cold-reducing. has heretofore been generally done byavcold-drawing operation which necessitates, reducing; or pointing one end-ofi the tubular-section in order-to pass it through the colddrawing die. so that: it can be grasped by-thedrawing tongs. This pointed section must lat'er-beremoved anddiscarded. as-scrap which addsaconsiderablytozthecostsof the product; particularly in the case ,of alloy: and'short tubular sections.

It is accordingly an object oftheapresent invention;to provide-a method and apparatus for economically cold-reducing pipe sections of various lengths. a p

The foregoing and further objectswill be apparent from the following specificationwhen read in conjunction, with they appended. drawing, wherein:

Figure 1 is a plan view. showing the apparatus 7 at'the start of aroma-reducing operation;

' Figure 2 isva similar viewshowing the workpiece partially reduced; and,

Figure 3 is a similar view after the cold-reduce ing operation has been completed and the;work= 'piece.=stripped-fromthe carrier-mandrel.

Referring more particularly to the drawing, the numeral 2 designates hydraulic cylinders adapted to reciprocate rams 4 carrying a crosshead 6 which is counterbored on the forward side to receive an annular pusher member 8. A mandrel l0, having an enlarged end portion or head II, is reciprocably mounted inside the pusher 8 and crosshead 6 and is adapted to be operated by a ram l2 and pressure cylinder I4.

Mounted forwardly of the crosshead 6 is a die holder H in which there is disposed concentrically about the mandrel In in its extended position, a reducing die l8. On the forward side of the die holder l6 are stripping fingers 20. It

the die. Further travel thereof is merely a waste of power; This permits the pusher to be of-quite is noted that the outside diameter of the pusher thin-cross sectionsince it cangbe quiteshort. In the case of'long workpieces, the'friction of the reduced tubing on the mandrel may, in. some cases, besufficient to clear the workpiece through the die without having the pusher 8 g0 therethrough. In such case, the cylinder l tmaybe made heavier so that it can be used to assist in pushing the unreduced section of the workpiece through the die. These'alternative modesof operation, usually depending on the length of the workpiece, are-made possible because of the floating; independently: acting: and controllable mandrel 1 l 0 and pusher 8:

Inifront oftherdie holder lfi'andinaxial alignmenttherewith, there, iszpreferably an electri- -.cally conductive coil 22;:whereby: a tubular sec"- tiondisposed therein-may be heated by induced currents, preferably high frequency currents. However, a suitable gas furnace or other'quick acting radiant 1 heating may be used In operation, a tubular. section or blank -W to be reduced is disposed in front of the mandrel 8 and the cylinder M is operated to push themandrelthroughthe workpiece. When'the front-,end of themandrel It isjust'through the workpiece W, the-cylinder I4 is made, inop'era-r tive so that the workpiece enters the die positioned on the forward end of the mandrel. The cylinders 2 are then operated to advance the rains 4 and crosshead 6 whereby the pusher member 8 engages the rear end of the workpiece and as it continues to advance, forces the workpiece through the die l8 to reduce the diameter and, in conjunction with the mandrel l0, reduces the wall thickness thereof. As soon as the workpiece is partially through the die and its forward portion drawn down tightly on the mandrel bar In, the cylinder M is made operative to assist or perform the drawing action, and, if necessary, when the workpiece is entirely through the die to push the mandrel with the workpiece forwardly so that the rear end of the workpiece I will advance beyond the stripping fingers 20. At

this point, the coil or other heating means may be energized to quickly heat the workpiece sufficiently to expand it slightly so as to permit the withdrawal of long workpieces from the mandrel. The cylinders 2 are then operated to withdraw the crosshead 6 and pusher member 8 and thereby permit the stripping fingers 2'0 to engage the a rear end of the workpiece. Continued actuation of the cylinders 2 causes the crosshead B to engage the head ll of the mandrel and thereby withdraw or assist in the withdrawal of the mandrel from the workpiece which is held by the stripping fingers 2B. The mandrel is then further withdrawn by action of the cylinder M to place it in workpiece loading position shown in Figures 1 and 3. The apparatus is then in position for the entry of another workpiece therein to be reduced in the foregoing manner.

The above described arrangement which provides for free longitudinal movement of the mandrel during the workpiece reducing operation, permits substantial area reductions and elongation which would not be possible if the mandrel did not have this floating action. Also by retracting the mandrel to permit positioning the workpiece, the stroke of the crosshead carrying the die can be reduced about 50% which simplifies press construction, speeds up operations and conserves power. When the workpiece is being pushed through the die, the mandrel will travel faster than the pusher sleeve 8 since areduction of area of the workpiece is taking place which results in its elongation. In other words, the speed of travel of the unreduced portion of the workpiece is less than that of the reduced portion. As the mandrel is tightly gripped by the reduced portion of W, the mandrel will take the speed of travel of that portion and as it is loosely entered into the unreduced portion or" the workpiece, it is free to travel at a different speed from that portion'of the workpiece, while the pusher speed is naturally the same as that of the unreduced portion of the workpiece.

While I have shown and described one specific embodiment of my invention, it will be understood that this embodiment is merely for the purpose of illustration and description and that various other forms may be devised within the scope of my invention, as defined in the appended claims.

I claim: a I

1. In apparatus for reducing tubular sections by passage through a reducing die, a reciprocable mandrel constructed and arranged to be extended through the reducing die to define the interior diameter of a workpiece reduced therebetween, a cylindrical pusher member having a slightly smaller outside diameter than the inside diameter of said die reciprocably mounted concentrically and externally of said mandrel, means for pushing said member through said die and means for stripping a reducing workpiece from said die.

2. In apparatus for reducing tubular sections by passage through a reducing die, a reciprocable mandrel constructed and arranged to be extended through the reducing die to define the interior diameter of a workpiece reduced therebetween and to float with a tubular section being reduced, a cylindrical pusher member having a slightly smaller outside diameter than the inside diameter of said die reciprocabl mounted concentrically and externally of said mandrel, means for pushing saidmember through said die and stripping fingers for stripping a reduced workpiece from said mandrel when said mandrel is withdrawn from said die.

.3. In apparatus for reducing tubular sections by passage through a reducing die, a reciprocable mandrel constructed and arranged to be extended through the reducing die to define the interior diameter of a workpiece reduced therebetween and to float with a tubular section being reduced, means to positively reciprocate said mandrel, a cylindrical pusher member having a slightly smaller outside diameter than the inside diameter of said die reciprocably mounted concentrically and externally of said mandrel, means for pushing said member through said :die independently of said mandrel, means on said mandrel adapted to be engaged by said pusher member pushing means whereby said mandrel reciprocating means and said pushing means may be conjointly operated to. withdraw said mandrel from a reduced workpiece.

' JOHN W. OFFUT'I.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 532,434 Van Fleet Jan. 8, 1895 1,722,787 Claus July 30, 1929 FOREIGN PATENTS Number Country Date 703,340 Germany Mar. 6, 1941 

